Unofficialbmw.com

ian_alex · Joined: 03 Oct 2006 Posts: 2

I have had a noise issue for several years and which is getting progressively worse as you might expect.
Nothing when cold but when hot at low revs under light load what I can best describe a a dull knock. Under heavy load eg a fast start it does not exist! In any event the noise goes away at higher revs.
With a stethoscope it seems to be from the timing chain area but it is not what I would regard as chain noise.
Various dealers have listened but no ideas except to disconnect Vanos which I did with no effect.
I thought about oil viscosity change with temperature perhaps related to chain tension but this is spring loaded!
What about hydraulic tappets? but location does not stack up
I intend to remove the cam cover to have a look but don't expect to see anything amiss.
There are no performance or any other issues.
Any thoughts or suggestions would be appreciated.

walshja · Joined: 03 Apr 2001 Posts: 1139 Location: guilford, ct, usa

the symptoms you are describing sounds similar to what I have, and I was told it was my VANOS. This was maybe 100k miles ago, I never fixed it, and other than the sound, there are no other symptoms.

I went to a slightly heavier oil once, and the noise did lessen, but never went away.

I was also told this is a common problem on my 325, which I think is the same engine on your 323, right? 2.5 liter?
_________________
joe

1994 325iC, 195k miles
http://home.comcast.net/~walshja/index.html <--- check it out

ian_alex · Joined: 03 Oct 2006 Posts: 2

Thanks for the reply. I will try disconnecting vanos again to see if it makes any difference.
regards